3. (A)
Question type: Identify A Flaw
There are a few reasons why this argument is flawed _ the main ones hinge on the fact that the two fish each angler picked may not be representative of the trout population as a whole. The methods of these anglers may attract trout of a certain maturity level, or the anglers may pick the largest of their catch for the biologists to weigh _ either of these considerations would skew what is being taken for the "average" size of a trout.
Answer choice (A) represents this flaw, and is therefore the correct answer.
(B) is not true. This isn’t anecdotal evidence.
(C) is irrelevant. The measurement is specifically for what the fish weigh at the beginning of the season.
(D) is irrelevant. This measurement is for this particular season only.
(E) is irrelevant. This argument is only about trout.